OK, so make two strings.
One 2v, and one 3v in each string.
Rlimit = (13.8v - (2v+3v)) / 20mA
Rlimit = 8.8/0.02 = 440 Ohms.
Since it's so close, we'll try 430 Ohms.
LEDcurrent = 8.8/430 = 20.46mA. That should be pretty comfy.

What if the generator was charging hard at 14.5v?
14.5v -5v= 9.5v; 9.5/430 = 22.1mA - still not horriffic.
Check the wattage: 9.5 x 22.1mA = 0.21; x2=.42, need a 1/2W resistor.
Check the current with a discharged battery:
11.7 - 5 = 6.7v; 6.7/430 = 15.6mA. You'll notice that it's dimmer, but it'll still be fairly bright.

I can't string them together cuz of the nature of the negitive. the oil light, high beam and neutral light have seperate ground wires, same positive lead. the signal lights have a common ground seperate positive leads.

They have to be wired individually

 

It sounds like you have the "Super Bright" LEDs. If running these at 20mA, your indicator lights could nearly blind you. Use a 1k resistsor for all of them, the light will still be very bright, but won't get overloaded.

--ETA: Pick "Wiring Diagram" with this calculator, it works for even 1 LED: LED series parallel array wizard

 

Yes they are super brights. So by 1k you mean 1000 ohm resisters?

I connected yet another led and resister. it worked once then went out. I checked current and it was down to 1v. Are these crappy resisters? do I need to stay away from certain ones?

 

How are you connecting it?

Should go V+ -/\/\/\/---->|--- -Batt
-------------- 1,000Ω - LED --- Negative
measure the voltage across the LED, it should be around 3V, there should be around 9-10V across the resistor, if the battery is 12-13V.

 

sorry dude, can't read yoru symboling.

I am connecting the resistor to the pos lead. I would like to dim them up too. That is a good thing.

What is going on with the voltage drops? is that the led burning out?

 

Hey, cool wizard.

I guess I have been connecting the resistor to the wrong side??? I am sure I read it goes on the pos lead.
According to the wiz a 640ohm resistor will work with both my 2 and 3v leds.
You say a 1k will still fire them but they will be dimmer? I think I will just go that way.

 

here are the specs

Emitted Colour : Green
Size: 5mm
Lens Color : Water Clear
Forward Voltage (V) : 3.0~3.6
Forward Current (mA):20
View Angle: About 25 degree.
Static Sense:Yes
Luminous Intensity: 15000mcd
Life Rating : 100,000 Hours
Free Resistors:
Supplied with free resistors for DC 12V

 

With your 2v LEDs and a 1k resistor supplied by 13.8v, you will get:
LEDcurrent = (13.8v - 2v) / 1000 = 11.8/1000 = 11.8mA current.

With your 3v LEDs and a 1k resistor supplied by 13.8v, you will get:
LEDcurrent = (13.8v - 3v) / 1000 = 10.8/1000 = 10.8mA current.

The LEDs will be about half as bright as they would be with 20mA going through them. They should still be plenty bright enough to see though.

I'm not sure why your LEDs are getting "zapped", but it may be due to static electricity, or it could be due to a relay somewhere having a bad diode across the coil. You could prevent that problem by adding a diode connected in reverse across the LED.

Here's what I'm talking about:

You're already using BAT, R1, D1, and S1 in your circuit. D2 is just a switching diode. You can pick up a pack of 10 of them from Radio Shack for a buck or two.

If there should be a reverse polarity voltage "spike" on the wiring, D2 will protect your LED.

 

Did you order these from the seller that includes the chinese tassle with the order (Forgot his seller name)

Friend bought from him, and I ordered some from same guy a while back due to his good reviews. The LEDs (RGB in one pack) I received came with resistors,and all of them worked great.

 

Did you order these from the seller that includes the chinese tassle with the order (Forgot his seller name)

Friend bought from him, and I ordered some from same guy a while back due to his good reviews. The LEDs (RGB in one pack) I received came with resistors,and all of them worked great.

No tossle from this guy.

http://stores.shop.ebay.com/accessories-less__W0QQ_armrsZ1

 

Never heard of that seller, but that doesn't mean they are junk.

Try the suggestion sarge put up. A 1,000Ω (1k, Brown-Black-Red) resistor between + and Long Lead of LED (+ side), then short leg of LED to Negative. Add a standard diode (not an LED) across the LED so that the band faces positive. It is more clear in the schematic sarge drew above.

Do you have a digital multimeter with current mode? If so, put the meter in 10A Mode, the positive lead on Bat +, and the negative lead to the resistor, leaving the rest of the circuit above the same. That will let us know how much current is actually flowing before the LED quits.

 

I checked the mA across the led and its only 18.4 with the resisters I got with it. When I first apply the meter that is then they continue to drop with time?

 

So, measure the voltage from the top of the resistor to ground.

What do you get?

11.7 volts, and you were measuring one of those 3.1v LEDs, right?

The current is slowly decreasing because your battery is slowly discharging.

 

My bat has dropped to 7.6v. I need to charge it.. Don't know whats happening there. its was a full charge yesterday. something must be grounding out and killin it.

I had to pull hte front end apart last night so the dash is haning in a mass of spaggetti.